Sometimes many newbies get their gambling life ruined by their first big hit winning, this is what mostly happens to those newbie that will think that he have suddenly developed a strategy to keep hitting such big winning on a consistent basis, this make things a bit tough for them along the way since they come to a point where resistant becomes an issues and at that time they will begin to lose uncontrollably.
And also the winning money goes to the wrong place. Empty and uncontrolled spending, which can lead to other addictions. For example, it can be alcohol addiction. I read about one such case. One family managed to win a lot of money. Several years passed and people were surprised by what happened to them. They became drunkards and drank away absolutely all the money. It was hard to believe, but this also happens.
That can happen, and not only in gambling. I remember a story of a popular boxer who made a lot of money because he is good at what he does, and winning many fights. Years later, or when he is near retirement, he spends all his money on gambling, alcohol, and women. After he depleted all his money, he became poor again, living in the province and didn't even have a house of his own or any savings.
Anyway, you are right that a gambler can win millions and just switch to another addiction because he badly wants to spend his money on a luxury that he hadn't experienced before.